Vehicles operating in an autonomous mode (e.g., driverless) can relieve occupants, especially the driver, from some driving-related responsibilities. When operating in an autonomous mode, the vehicle can navigate to various locations using onboard sensors, allowing the vehicle to travel with minimal human interaction or in some cases without any passengers.
Group driving styles, relatively stable part of group driving behaviors at the strategic, tactical, and operational levels, varies in different areas due to local social norms and cultural values, surrounding environments and traffic conditions, and local weather. For example, in suburban areas, people's driving styles are more on a defensive driving side and in urban areas people are more on an aggressive driving side. In addition, people drive more cautiously in a raining day than usual.
An autonomous vehicle (also referred to as an autonomous driving vehicle or ADV) needs to adopt local driving styles (or similar ones) to keep the traffic flow harmonious, and to make a trip safe and time efficient. For example, an autonomous vehicle may take a much longer time to complete a trip if a very defensive driving strategy is adopted in an urban area because most of vehicles are more on an aggressive driving side, as they may cut in frequently. Alternatively, an autonomous vehicle may have a higher risk of an accident if an aggressive driving style is used in a raining day as all surrounding vehicles are driving cautiously and slowly. A social driving style has many aspects and may change dynamically thus it is hard to preconfigure a set of rules for that in an autonomous vehicle.